Integrated dynamic blending apparatus

ABSTRACT

The present invention relates to an apparatus for dynamically blending two or more fluids to form a blended gaseous mixture. The apparatus integrates a pressure regulation section and a dynamic adjusted blending panel into a single enclosure that allows for custom blending at the fabrication tool site which permits such blending in a more efficient and less complex manner.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation in part of Ser. No. 09/799,644 filed on Mar. 6, 2001 which in turn is a divisional application of Ser. No. 09/174,196, filed Oct. 16, 1998, now U.S. Pat. No. 6,217,659, all of which are assigned to Air Products and Chemical, Inc. and all of whose entire disclosures are incorporated by reference herein.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to an apparatus for dynamically blending two or more fluids to form a blended gaseous mixture and more particularly, for combining a semiconductor liquid or gas with a carrier gas for delivery to a fabrication tool in a more efficient and less complex manner by integrating a pressure regulation panel with a dynamically adjusted blending panel all within the same enclosure.

[0003] Current practice for chemical vapor deposition and etching applications is to either provide pre-manufactured gaseous mixtures or to blend within the semiconductor manufacturing tool to enable chemically balanced reactions. Pre-manufactured mixtures, which typically include a minor high-value component mixed with a major low-value carrier or co-reactant are limited to the operating storage volume and pressure in the delivery container. Blending at the tool may require evaporation of liquefied compressed gases from the supply source and delivery in gas phase directly to the process mass flow controller (MFC). Heat jacketing of the cylinders, and tracing of the gas cabinet and transfer lines may be required to inhibit re-condensation in the delivery line and pressure fluctuations which adversely impact the manufacturing process. This depends on the dew-point temperature of the process fluids, the process chamber operating pressure and dynamic pressure drop in the transfer line, Heating and heat tracing add operating expense, and create operational and maintenance concerns for semiconductor production facilities. Recent increases in the product flow and chamber pressure requirements have made it difficult to maintain the current practice.

[0004] In particular, semiconductor materials can be delivered as liquids or gases to the customer site, but it is typical to consume materials in the gaseous phase inside the fabrication tool. Liquids may therefore have to be evaporated before final process application. One way to accomplish this is via a bubbling technique, where an inert or co-reactant gas (the carrier) flows through a liquid inventory to evaporate the liquid. The bubbling technique typically strives to saturate the carrier gas to a specified temperature and pressure, thereby insuring a consistent mixed stream composition. However, one problem of using this technique is that the bubbled stream is saturated at a given temperature, and a decrease in temperature in the delivery line may lead to re-liquefaction of the evaporated liquid. Re-liquefaction impacts the stream composition and disturbs the manufacturing process.

[0005] As is well-known in the art, another way to evaporate liquid is to drop the pressure of the liquid. This is typically done by placing a pressure regulator in the delivery line between the source container and the fabrication tool. This technique is fine for liquids that have a significant (approximately greater than 80 psig) vapor pressure, but becomes a concern for lower vapor pressure liquids. In those systems, the delivery pressure may approach the liquid vapor pressure since a limited amount of pressure drop may be taken across the pressure regulator. Since the vapor pressure and delivery pressure are close, the evaporated liquid has the potential to re-liquefy in the delivery line and, as mentioned earlier, re-liquefaction causes processing problems in the fabrication tool.

[0006] For these lower vapor pressure materials or the saturated stream from the bubbling technique, customers are typically required to heat and insulate the delivery line. A heat trace is a flexible heating wire that can be attached to the outside of the delivery line. In combination with insulation, the heat trace maintains the delivery piping temperature above the re-liquefaction temperature. However, one problem with using the heat trace is that the heat trace is unreliable and expensive to maintain and operate.

[0007] One way to circumvent the re-liquefaction issue is to pre-mix the evaporated liquid and the carrier gas to a fixed composition, where the pre-mixed stream cannot be re-liquefied even at the lowest delivery line operating temperature. This can be done in batches, delivered to the site in fixed volume containers. There are benefits to mixing at the customer site. These benefits include improved supply logistics, flexibility of stream composition, potential safety implications, and mixture stability.

[0008] The following U.S. patents pertain to gas or liquid blending or mixture systems: U.S. Pat. Nos. 3,751,644 (Mayer); 3,771,260 (Arenson); 3,856,033 (Strain, et al.); 3,948,281 (Strain, et al.); 4,277,254 (Hanson); 4,345,612 (Koni, et al.); 5,419,924 (Nagashima, et al.); 5,476,115 (Lalumandier, et al.); 5,495,875 (Benning, et al.); 5,575,854 (Jinnouchi, et al.); 5,690,743 (Murakami, et al.); 5,989,345 (Hatano); and 6,217,659 (Botelho et al.). With particular regard to U.S. Pat. No. 5,989,345 (Hatano), it should be noted the Hatano patent is limited to liquid or liquefied compressed gas minor-components; requires static mixing volumes as opposed to dynamic blending; fails to recognize the potential to eliminate heat tracing of delivery lines; and does not cover the improvement in delivery pressure.

[0009] Thus, there remains a need for an apparatus that can blend a fluid, either a liquid or a gas, with a carrier gas for delivery to a fabrication tool in a more efficient and less complex manner by integrating pressure regulation panels with a dynamically adjusted blending panel all within the same enclosure.

BRIEF SUMMARY OF THE INVENTION

[0010] An apparatus for dynamically blending a semiconductor fluid with a carrier gas for use by a fabrication tool at the fabrication tool site. The apparatus comprises a single enclosure and comprises: a first and second source of semiconductor fluid (e.g., a gas or a liquid) that supply the semiconductor fluid in alternation to a fluid blender and wherein the first and second sources operate so that one of the first and second sources is providing the semiconductor fluid to the fluid blender while the other one of the first and second sources is in standby; the fluid blender comprises a first and second flow train for passing the semiconductor fluid from the first or second source that is providing the semiconductor fluid, and wherein each of the first and second flow trains comprises: a semiconductor fluid flow path having a first output; a carrier gas flow path, coupled to a source of carrier gas, and having a second output; and a mixer for mixing the first and second outputs into a third output which forms an output flow to the fabrication tool; and wherein the first and second flow trains operate in alternation such that one of the first and second flow trains is providing the output flow while the other one of the first and second flow trains is in standby.

[0011] A method for dynamically blending a semiconductor fluid with a carrier gas for use by a fabrication tool at the fabrication tool site. The method comprises the steps of: providing a single enclosure that houses two semiconductor fluid sources; operating the two semiconductor fluid sources such that one of the sources supplies the semiconductor fluid (e.g., a gas or a liquid) to a downstream fluid blender located in the single enclosure while the other one of the sources is on standby; configuring the fluid blender to provide two semiconductor fluid flow paths, and wherein each of the paths is mixed with a carrier gas from a carrier gas supply and forms two mixture outputs; and operating the two semiconductor fluid flow paths such that one of the two mixture outputs supplies the semiconductor fluid blended with the carrier gas to the fabrication tool and wherein the other one of the two mixture outputs is on standby.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

[0012] The invention will be described by way of example with reference to the accompanying drawings, in which:

[0013]FIG. 1 is a block diagram of the apparatus of the present invention;

[0014]FIG. 2A is a process flow diagram of the minor component source supply and dual process panels in the present invention; and

[0015]FIG. 2B is a process flow diagram of the component blender and dual flow trains of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0016] The concept of the present invention is an advantage over current technology, as it enables greater flexibility in process recipes and reduces the onsite facilitation requirements. In particular, the present invention is an improvement of the apparatus disclosed in U.S. Pat. No. 6,217,659 B1 (Botelho, et al.), whose entire disclosure is incorporated by reference herein. U.S. Pat. No. 6,217,659 (Botelho, et al.) discloses an apparatus for dynamically blending a vaporized liquid with a carrier gas to deliver an unsaturated vapor mixture. As will be discussed in detail later, the present invention improves on this apparatus via an integral gas cabinet with dynamic blending panel, thereby enabling delivery of adjustable mixtures to chemical vapor deposition and etching processes.

[0017] As can be seen most clearly in FIG. 1, the present invention replaces all of the hardware to the left of the check valve 138 in the purge path and all of the hardware to the left of the flow elements (FE) 122/48 in the carrier gas path and the semiconductor liquid path, respectively. In addition, the present invention 320 comprises a semiconductor (SC) liquid or gas supply 322 therein and may also comprise a carrier gas supply 324 therein, or the carrier gas supply 324 may be external to the present invention 320; similarly, the present invention may also comprise a purge gas supply 326 therein, or the purge gas supply 326 may be external to the present invention 320. It should be noted that another improvement over the system of U.S. Pat. No. 6,217,659 (Botelho, et al.) is that the SC supply can be either a gas or a liquid, not just a liquid as shown in U.S. Pat. No. 6,217,659 (Botelho, et al.).

[0018] The present invention 320 integrates pressure regulation panels with a dynamic blending panel into a single enclosure, or gas cabinet, 321. In particular, FIG. 2A comprises a process flow diagram for a pressure regulation section 328 of the present invention 320 and FIG. 2B comprises a process flow diagram for a dynamic adjusted blending panel section 330 of the present invention 320.

[0019] It should be understood that, although not shown, a controller (e.g., a microcontroller or programmable logic controller (PLC), such General Electric's Series 90-30 PLC, etc.) is coupled to the various valves and transducers for controlling the appropriate valves, as discussed below, for operating the various process flows in order to deliver the blended semiconductor fluid with the carrier gas to the fabrication tool at the customer site, as well as for purging the various process flow paths, as described below.

[0020] The SC fluid (e.g., liquid or gas) described in this application may comprise, but is not limited to, tungsten hexafluoride, trimethylsilane, etc., and is also referred to as the “minor process component.”

[0021] As can be seen in FIG. 2A, the pressure regulation section 328 comprises a dual process wherein two SC fluid supplies 322A/322B are coupled to respective feed forward lines 332A/332B. These SC fluid supplies 322A/322B and their respective feed forward lines 332A/332B form redundant feed forward paths; thus, while one feed forward line 332A or 332B is providing the semiconductor fluid from its respective supply 322A or 322B, the other feed forward line is on standby. Each of these feed forward lines 332A/332B is coupled to a respective port of a 3-port automatic valve 334; in particular, port 334A is coupled to feed forward line 332A, port 334B is coupled to feed forward line 332B and port 334C forms the pressure regulation section output 335 which is passed onto the dynamic adjusted blending panel section 330. For example, during operation, when feed forward line 332B is active all three ports 334A-334C of valve 334 are open, the controller closes valve 333A in feed forward line 332A; therefore, only the semiconductor fluid from the source 322B passes through the valve 334. As this supply 322B is depleted, and if the supply 322B is supplying a SC gas, then a pressure transducer PT1B detects the low pressure of the supply 322B and informs the controller which then closes the port 334B while opening the valve 333A, thereby allowing the standby feed forward line 332A to now supply the SC gas from the supply 322A. With the feed forward line 332B now on standby, a new canister can be introduced for supply 322B. Once the supply 322A becomes depleted, a corresponding pressure transducer PT1A detects the low pressure of the supply 322A and informs the controller which then closes valve 333A while opening the port 334B, thereby restoring the feed forward line 332B as the active SC gas supply line, and thus the cycle is repeated.

[0022] It should be understood that where the SC supplies 322A and 322B supply SC liquid rather than a gas, the pressure transducers PT1A/PT1B are replaced with mass detectors, e.g., scales, for detecting the weight of the canisters of the supplies 322A/322B. These scales inform the controller when the SC liquid in the respective canisters are being depleted and the controller then operates the valves as discussed previously with respect to the use of SC gas.

[0023] Each feed forward line 332A/332B comprises a respective vent path 336A/336B that supplies a vent 338 and Venturi source 340 to each feed forward line 332A/332B through a respective 3-port automatic valve 342A/342B. It should be noted that a blender vent path 339 is provided from a vent 338 Nenturi source 340 to the dynamic blending panel 330. Furthermore, to purge each of the feed forward lines 332A/332B, a respective purge path 344A/344B is coupled through a respective 3-port automatic valve 346A/346B to the purge gas supply 326. It should also be noted that a blender purge path 347 is provided from the purge gas supply 326 to the dynamic blending panel 330 for purging the SC fluid lines and the carrier gas lines in the dynamic adjusted blending panel 330. The purge gas may comprise gases such as nitrogen, argon, etc.

[0024] As can be seen in FIG. 2B, the dynamic adjusted blending panel 330 comprises a dual flow train wherein the pressure regulation section output 335 is divided into two distinct SC fluid paths 348A and 348B. In addition, a corresponding pair of carrier gas paths 350A and 350B, supplied from the carrier gas supply 324, are provided for mixing with their respective carrier gas paths 350A/350B via respective mixers 352 and 354; the carrier gas is also referred to as the “major process component” and may comprise gases such as oxygen, nitrogen, hydrogen, etc. The output of each mixer 352 and 352, namely 356 and 358, respectively, is coupled to a respective port of a 3-port automatic valve 360; in particular, port 360A is coupled to mixer output 356, port 360B is coupled to mixer output 358 and port 360C is coupled to the tool supply/system purge output 362. This dual flow train configuration of SC fluid path/carrier gas path also provides redundancy with one of the SC fluid paths 348A/348B and its corresponding carrier gas path 350A/350B being active while the other is a standby. Alternatively, these two flow trains can be simultaneously active for delivering a higher flow capacity to the fabrication tool but the preferred method is the redundant configuration, with one being active and the other on standby. There are two basic triggers for switching between these two flow trains:

[0025] (1) in the event that one of the monitored process parameters (e.g., flow, pressure, composition, etc.) falls outside of specification, for example, indicative of a component failure in the SC fluid path 348A/348B and/or its corresponding carrier gas path 350A/350B; or,

[0026] (2) maintenance routine needs to be performed on one of the dual flow trains. In either of these events, the controller can switch to the standby flow train.

[0027] For example, during operation, when the SC fluid path 348A and its corresponding carrier gas path 350A are active, all three ports 360A-360C are open and the controller closes a port 364B of another 3-port automatic valve 364 while leaving the other ports 364A and 364C open. Furthermore, the controller also opens a port 365A of an L-port automatic valve 365 which has another port 365B that is always open. Simultaneously, the controller also closes a port 366B of another 3-port automatic valve 366 while leaving the other ports 366A and 366C open; in addition, the controller also opens a port 367A of another L-port automatic valve 367 which has another port 367B that is always open. Controlling these valves in this manner, permits the SC fluid path 348A and its corresponding gas path 350A to supply the SC fluid/carrier gas mixture to the fabrication tool through the output 362, while the SC fluid path 348B and its corresponding gas path 350B is on standby. Should it be necessary to switch to the standby flow train, namely, SC fluid path 348B and its corresponding carrier gas path 350B, the controller reverses this process by closing port 360A of valve 360, closing port 365A of valve 365 while opening port 364B of valve 364, closing port 367A of valve 367 and opening port 366B of valve 366.

[0028] It should be noted that both the SC fluid paths 348A/348B, as well as the two carrier gas paths 350A/350B are coupled through respective 3-port automatic valves 370-376 to the blender purge path 347 to permit all of these paths to be purged at the appropriate time. The purge flow from all of these paths exhausts through the tool supply output 362 also, hence the reference to the output 362 as the “tool supply and system purge.”

[0029] By combining the pressure regulation section 328 and the dynamic adjusted blending panel 330 into one enclosure 321 as an integral apparatus, the present invention 320, which is located at the customer site, provides the following benefits:

[0030] 1) Utilizes source reactants at 100% composition, so that more product can be delivered per unit volume of delivery container. The carrier or coreactant gases are typically the major component in the mixture (>50% composition), and widely available at the customer site.

[0031] 2) Allows flexibility of stream composition. Pre-mixed streams have a fixed composition. Streams mixed onsite can be directly modified to meet the specific process requirements. In particular, the present invention 320 allows for the direct mixing of two components to process-recipe specific composition, variable by the customer from the PLC (not shown) instead of waiting for a new mix or having to mix within the tool.

[0032] 3) Avoids heat trace by blending a stream so that its composition remains below the re-liquefaction temperature in the delivery line. In particular, the present invention 320 permits the elimination of delivery heat tracing for low vapor pressure liquefied compressed gases when dew-point-suppression exists.

[0033] 4) Potential to significantly increase the connection life cycle of the delivery supplies 322A/322B in the gas cabinet 321, since the delivered content of the minor process component (i.e., the SC liquid or gas) can be maximized when compared to pre-manufactured mixes.

[0034] 5) Following on point 3 above, if condensation concerns can be eliminated, the delivery/blending system can be remotely located from the general tool area, improving space availability around the tool.

[0035] 6) Following on point 5 above, the mixed stream may be available at a much higher delivery pressure since the minor component delivery pressure would not have to be reduced below the dew-point pressure at the lowest delivery line temperature. Also, higher available pressure assists the performance of downstream pressure (VMB) and flow (MFC) regulation components.

[0036] 7) Potential elimination of delivery heat tracing for low vapor pressure liquefied compressed gases when dew-point-suppression exists.

[0037] The present invention has been illustrated with reference to one or more specific embodiments, however, the full scope of the present invention should be ascertained from the claims which follow. 

1. An apparatus for dynamically blending a semiconductor fluid with a carrier gas for use by a fabrication tool at the fabrication tool site, said apparatus comprising a single enclosure comprising: a first and second source of semiconductor fluid that supply said semiconductor fluid in alternation to a fluid blender, said first and second sources operating so that one of said first and second sources is providing said semiconductor fluid to said fluid blender while said other one of said first and second sources is in standby; said fluid blender comprising a first and second flow train for passing said semiconductor fluid from said first or second source that is providing said semiconductor fluid, each of said first and second flow trains comprising: a semiconductor fluid flow path having a first output; a carrier gas flow path, coupled to a source of carrier gas, and having a second output; and a mixer for mixing said first and second outputs of into a third output which forms an output flow to the fabrication tool; and wherein said first and second flow trains operate in alternation such that one of said first and second flow trains is providing said output flow while said other one of said first and second flow trains is in standby.
 2. The apparatus of claim 1 wherein each of said first and second sources of semiconductor fluid comprises: a feed forward line having a first end coupled to a respective semiconductor fluid supply and a second end coupled to a respective port of a multi-port valve; a vent path having a third end coupled to said first end and a fourth end coupled to a vent and a Venturi source; and a purge path having a fifth end coupled to said first end and a sixth end coupled to a purge gas supply.
 3. The apparatus of claim 2 wherein said fluid blender further comprises a blender vent path that is coupled to said vent and said Venturi source at one end and which is coupled to said third output of each mixer and coupled to each carrier gas flow path.
 4. The apparatus of claim 2 wherein said fluid blender further comprises a blender purge path that is coupled to said purge gas supply at one end and which is coupled to said first and second flow trains and to said carrier gas flow paths at its other end.
 5. The apparatus of claim 1 wherein said semiconductor fluid is a liquid.
 6. The apparatus of claim 2 wherein said semiconductor fluid is a gas.
 7. The apparatus of claim 1 wherein said carrier gas supply is internal to said enclosure.
 8. The apparatus of claim 2 wherein said purge gas supply is internal to said enclosure.
 9. A method for dynamically blending a semiconductor fluid with a carrier gas for use by a fabrication tool at the fabrication tool site, said method comprising the steps of: providing a single enclosure that houses two semiconductor fluid sources; operating said two semiconductor fluid sources such that one of said sources supplies said semiconductor fluid to a downstream fluid blender located in said single enclosure while the other one of said sources is on standby; configuring said fluid blender to provide two semiconductor fluid flow paths, each of said paths being mixed with a carrier gas from a carrier gas supply and forming two mixture outputs; and operating said two semiconductor fluid flow paths such that one of said two mixture outputs supplies said semiconductor fluid blended with said carrier gas to the fabrication tool and wherein the other one of said two mixture outputs is on standby.
 10. The method of claim 9 wherein said step of providing a single enclosure that houses two semiconductor fluid sources comprises providing a respective feed forward line coupled between a respective semiconductor fluid source and said fluid blender, said method further comprising the steps of: coupling each of said respective feed forward lines to a vent and a Venturi source; and activating said vent and said Venturi source to vent said feed forward lines.
 11. The method of claim 9 wherein said step of providing a single enclosure that houses two semiconductor fluid sources comprises providing a respective feed forward line coupled between a respective semiconductor fluid source and said fluid blender, said method further comprising the steps of: coupling each of said respective feed forward lines to a purge gas supply; and activating said purge gas supply to purge said feed forward lines.
 12. The method of claim 11 wherein said purge gas supply is located within said single enclosure.
 13. The method of claim 9 wherein said step of configuring said fluid blender comprises providing a respective carrier gas flow path that is coupled between said carrier gas supply and said respective semiconductor fluid flow paths, said method further comprising the steps of: coupling said semiconductor fluid flow paths and said carrier gas flow paths to a vent and Venturi source; and activating said vent and Venturi source to vent said semiconductor fluid flow paths and said carrier gas paths.
 14. The method of claim 9 wherein said step of configuring said fluid blender comprises providing a respective carrier gas flow path that is coupled between said carrier gas supply and said respective semiconductor fluid flow paths, said method further comprising the steps of: coupling said semiconductor fluid flow paths and said carrier gas flow paths to a purge gas supply; and activating said purge gas supply to purge said semiconductor fluid flow paths and said carrier gas paths.
 15. The method of claim 11 wherein said purge gas supply is located within said single enclosure.
 16. The method of claim 9 wherein said semiconductor fluid is a liquid.
 17. The method of claim 9 wherein said semiconductor fluid is a gas.
 18. The method of claim 9 further comprising the step of positioning said carrier gas source within said single enclosure. 